An air-to-air aftercooler (ATAAC) configured to cool compressed air from an air compressor is disclosed. The ATAAC may comprise a first header. The first header may include a plurality of slots each having a recessed groove. The ATAAC may further comprise a plurality of core tubes each including a first end inserted in a respective one of the slots of the first header. The ATAAC may further comprise a plurality of mechanical joints each connecting the first end of one of the core tubes to the first header. Each of the mechanical joints may include a C-ring inserted in the recessed groove of one of the slots, and a clamp clamping the core tube to the first header. The C-ring and the clamp may both be formed from a metallic material.